Impulse delay apparatus



Jvvucmfon 7 Sheets-Sheet l i00 000 00 0 o (D CONRAD H. HOEPPNER C. H. HOEPPNER IMPULSE DELAY APPARATUS AAAAAA vvvvv March 18, 1952 Filed March 18, 1946 AAAAA vvvvv mum vvvvv II II March 18, 1952 c. H. HOEPPNER IMPULSE DELAY APPARATUS 7 Sheets-Sheet 2 Filed March 18, 1946 L ff: mm

W I IJH m Swumflfob CONRAD H. HOEPPNER March 18, 1952 c. H. HOEPPNER 2,589,254

IMPULSE DELAY APPARATUS Filed March 18, 1946 7 Sheets-Sheet 5 INVEN TOR.

CONRAD H. HOEPPNER March 18, 1952 c. H. HOEPPNER IMPULSE DELAY APPARATUS 7 SheetsSheet 4 Filed March 18, 1946 a CE Cam $8 C C C v C C m d c c c F I: C o m C C mom C m C C 03C C a CM C C C C m Q C C C C C? m c E at i M K II w an v mHm INVENTOR. CONRAD H. HOEPPNER March 18, 1952 c. HOEPPNER 2,589,254

IMPULSE DELAY APPARATUS Filed March 18, 1946 7 Sheets-Sheet 5 m z N LIJ J 05 Q 2 m 0 o z (7, T o o wvww MMMM L wwwv -L INVENTOR. CONRAD H. HOEPPNER aiimmw GATING MULTIVIBRATOR 7 Sheets-Sheet 6 C. H. HOEPPNER IMPULSE DELAY APPARATUS U llllllpl INVENTOR. CONRAD H. HOEPPNER altmmazg III GATE GENERATOR March 18, 1952 iled March 18, 1946 C. H. HOEPPNER IMPULSE DELAY APPARATUS 7 Shegts-Sheet 7 I: I: I: I

INVENTOR. CONRAD H. HOEPPNER BY W Patented Mar. 18, 1952 UNITED STATES PATENT OFFICE (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) This invention relates broadly to electronic control circuits and in particular to circuits for the production of delayed electrical signals and for the production of pulse groups of selectable structure.

It is possible to construct artificial lines comprising multiple sections of inductance and capacitance which will provide a delay in the transmission of an electrical signal of the order of 100 micro-seconds without sacrificing entirely such desirablefeatures as high accuracy, low attenuation, and low distortion. When, however, an attempt'is made to extend the delay of such an artificial line to several times the figure given, merely by increasing the number of sections, a distinct loss in accuracy and dependabilit of operation results. In its proper delay period range, however, the precision of the artificial line section offers a valuable basis for apparatus which undertakes to provide delays of greater total duration.

In certain pulsed radio frequency communication and control work, the intelligence to be conveyed or the function to be instituted is defined by the arrangement of the members of a series of impulses.

Thisarrangement of signals mayv be altered simply by number or by time occur-" the sole requirement, it would appear that arti-v ficial delay lines or stable oscillators would constitute a ready answer to the problem. The situation is, however, complicated, in all-but the more simple cases, by the necessity for selectability, i. e., the ability to include or exclude any member of aseries of impulses and the necessity for 'a series of impulses having relatively long overall time durations.

It is therefore an object of this invention to provide method and apparatus forgenerating a delayed signal.

It is another object of this invention to provide a method and apparatus for generating a delayed signal which increases the useful range of artificial delay lines or other means of delaying electrical impulses.

It is another object of this invention to provide means and method for securing a delay interval of extended length and high accuracy.

It is another object of this invention to provide apparatus for generating signals delayed a selectable interval of time.

It is .another object of this invention to providemethodand apparatusfor producing a series ofsignals.

It is another object of this invention to provide method and apparatus for producing groups of signals of selectable group structure.

It is another object of this invention to provide apparatus of low power requirement .for producing a group of signals of selectable group structure.

Other objects and features of this invention will become apparent upon a careful consideration of the following detailed description when taken together with the accompanying drawings in which:

Fig. 1 is the circuit diagram of one exemplary embodiment of this invention;

Fig. 2 is a series of waveforms useful in explaining the operation of .the circuit of Fig. 1;

Fig. 3 is another series of waveform useful .in

explaining the operation of the circuit of Fig. .1;

Fig. 4 is another series of waveforms useful in explaining the operation of the circuit of Fig. '1;

Fig. 5 is the circuit diagram of a variant exemplary embodiment of the invention;

Fig. 6 is a series of waveforms useful in explaining the operation of the circuit of Fig. '5;

Fig. 7 .is the circuit diagram of another variant embodiment of this invention; and

.Fig. 8 is a series of waveforms useful in explaining the operation of the circuit of Fig. 7.

The basic principle underlying this invention is that if two series of recurrent signals of slightly diiTerent periodicity be produced simultaneously and an instant of time be chosen such that there is a predetermined relation between two contemporaneous signals, i. e., a predetermined phase relation between the series, each successive member of one of the series will'become separated from each corresponding successive member of the otherseries by an interval of time separation which changes uniformly. In accordance with the particular predeterminedrelation, the change may be made to represent an increase or it may be made to represent first, a decrease, and then ,an increase.

.For an explanation of means for .and method .of .applying this .and other principles in ya ,practical embodiment of this invention, reference is now had to Fig. 1 which is the circuit diagram of apparatus for producing a group of signals of selectable group structure. In this Fig. 1, vacuum tube I together with its associated circuit components represents .a means responsive .to an input signal at terminals 2 .for producing a gating voltage of ypredetermined time .duration. In the form shown it is known as a self-returning or one-shot multivibrator inasmuch as .only left-hand tube section IAconducts inthe quiescent condition but right tube section IB may be caused to conduct and left hand tube section IA to be cut off for a definite interval of time in response to an input signal at terminals 2. The duration of the interval during which section IA remains cut off is determined substantially by the RC circuit comprising resistor 3 and capacitor 4. Adjustment of either one of these results in adjustment of the non-conducting period of section IA. The non-conducting period is characterized by a positive voltage of definite time duration which appears at plate 5 of tube I. This positive voltage may be used as a gating voltage to key the operation of other circuits for a predetermined interval of time.

One such circuit responsive to the gating voltage of multivibrator I is that including vacuum tubes 8, 9, and ID. This circuit represents a means for generating a series of electrical signals of definite duration and periodicity. In particular, multigrid vacuum tube 8, together with parallel resonant circuit I! and the other immediately associated circuit components consti-.

characteristic that it will produce at screen I3 a sinusoidal voltage which always starts in a definite phase and achieves the same amplitude on had jointly to the circuit of Fig. l and the waveforms of Fig. 2. In Fig. 2, waveform 25 is representative of an input signal at terminals 2 of Fig. 1. Waveform 26 is representative of the gating voltage produced by multivibrator I which appears at plate 5 and is employed to key oscillator 8 into operation at grid I4. Waveform 21 is representative of the sinusoidal voltage which appears on screen grid I3 of oscillator 8 when it is keyed by the gating voltage. The distorted waveform at plate I5 of tube 8 is represented by 25 and trailing edges are sloping and, superposed waveform 28. It will be noted that this voltage is unidirectional with respect to quiescent level 28A and that, loosely speaking, it is opposite in phase to the sinusoid at screen I3. The leading 30 tion to a cutoff condition and conversely. Negthe first cycle as is maintained in steady operaheld quiescently with respect to the cathode of tion when tube 8 is unbiased by the application of a positive signal at control grid I4. The starting phase in the circuit shown is such that the first half cycle at screen grid I3 is negative.

A similar oscillatory voltage appears at plate I5 of tube 8. This voltage, which is unidirectional. with respect to the potential existing at plate I5' in the quiescent condition of the circuit, is not,

inthis embodiment, sinusoidal as might be expected. The coupling between control grid I2 and screen grid I3 has been made tight enough through choice of capacitor I6 to overdrive the plate and distort the expected sinusoid. This I distortion results in a waveform which is roughly quired to drive the tube from fully conducting to cutoff or from cutoff to fully conducting, squares up the output of plate I5.

This is accomplished by virtue of the fact that only a small segment of a sloping wavefront, representing a short interval of time, applied at grid I1 is amplified by the tube and appears at plate I8 as an abrupt change. Grid I I is held at substantially cathode potential during quiescence by the direct connection made to 3+ potential through resistors I9 and 28 and tube 9 is thus normally in a heavily conducting condition. In accordance with the ratio of resistors I9 and 20, variable by adjustment of resistor 20, a positive potential exists at junction 2|. It will be seen that the operation lecting the small potential drop from grid to cathode in tube 9, the difference between potential level 28B and 28A represents the value of the positive potential at which junction 2I is tube 9. It will be seen that, by adjusting resistor 20 to change the potential of junction 2|, the segments of the leading and trailing edges affecting tube 9 may be chosen and thus the in- 40 stants in time when tube 9 starts and finishes "each square wave may be chosen. This square wave is illustrated in Waveform 29 which also illustrates the fact that the leading and trailing edges of the voltage appearing at plate I8 of '45 tube 9 coincide in time with the particular segsister 32, continues and completes the recurrent signal generating process. The square wave produced by tube 9, as represented by waveform 29, is amplified and inverted by tube I9 and appears as waveform 33 at plate 34. After differentiation,

the output as it appears at grid 35 of multigrid vacuum tube 36 is a series of signals of a frequency determined by oscillator 8 and is represented by waveform 31.

The three tubes 8, 9 and I0 comprise a means responsive to an input signal for generating a series of recurrent signals the initial impulse of which occurs in a predetermined time relation to the input signal.

The four tubes 38, 39, 40 and 4| comprise a second means also responsive to an input signal for generating a series of recurrent signals the initial impulse of which occurs in a predetermined time relation to the input signal.

This second means is controlled at grid 42 of tube 38 by the same gating voltage which controls the first means. Its operation, up to the output circuit of tube 39, is the same as that of the first means up to the output circuit of tube 9. The components of the output circuit of tube 39 comprising capacitor 44, resistor 45, and resistor 45,-a1eso-hosen, in combination with the grid to cathode resistance of tube 40 that capacitor i-fias'sumes a definite charge during each positive square pulseat-plate -41 of tube '39. This charge, which is coll'ected by virtue of grid current flow in tube 40, is just sufficient t'ohold tube 40 cut oif'foran interval of time at the end of the posi- 'tive"pulse'equal to a half cycle at the resonant frequency oi'the parallel-combinationof inductance-48 and-capacitor tli. Grid'50'of tube l'fl is "returned to ground potential so that tube 45 is normallyconducting heavily through inductance 48. When tube*40 is cutoff for the half cycle interval/there appears at plate 51 a positive half cycle of "a 'sine wave. The oscillations which tendtopersist in the plate circuit of tube 40 are aborted'by-th'e resumptionof conduction by tube 40. This positive half cycle is of a nature such 'thatitmay'betransmitted bya delay line with 'afmi'nimum of distortion. It is applied to tube '41 which, by cathode follower action, provides a low impedancemeans for driving delay line 55. Switches 56 through 5| are connected to tapped points on delay line 55 through unilateral impedance elements, or simply capacitatively, to deliverimpulses to the grid 62 'after delay thereofbyselectable intervals of time. If a series'of signals is'applied to tube {41, each member of the se'ries"will be similarly delayed. If two or more 's'witche'sareclosed, and 'a series of impulses is appliedto tube '41, a corresponding two or more series of signals'each delayed a respective interval of time will be applied to tube 35 from the tapped points on the delay line.

Jo'l'nt 'rference'is'now had'to Fig. l and Fig. 3 for further explanation of the'foregoing. In Fig.

"3, waveform B5 is representative of an input impulse signal at terminals 2 of Fig. 1 (same significance --as waveform 25 of Fig. 2). In waveform 66 are shown the square wave pulses which appear atplate 4'! of tube 39 in response to this input impulse. Waveform 51 represents the resulting signal at grid-55 of tube 48 and Waveform 68 illustrates the series of signals applied by tube 4| to delay line 55. It should be noted here that initial signal 68A of waveform 58 may beshifted in time relation to the input signal of Waveform 65 by adjustment of resistor 59 associated with tube 39 just as the initial member of the series produced by the first described means could be shifted in time relation to the input signal by adjustment of resistor 25. From this it will be seen that control is thereby achieved over the time relation between the initial member of each of the series.

"Tube 35 represents a means of combining impulses produced by the sequence of tubes 8, 5, and with those produced by tubes 33, 39, 453 and 4|. Both grid 35 and grid 52 are so biased in the quiescent condition by connection to C- potential that tube 36 may only conduct when both grids receive positive unbiasing voltages simultaneously. Thus, an output signal appears at terminals 10 when, and only when, signals point on delay line 55 to which switch 51 .is'connected is chosen to delay the series of impulses at tube 41 the amount required to bring the seeone member of that series into time coincidence withf the-second member of the series applied to grit-1850f tube 36. It will be'recognized that the =diiTerence in periodicity of the two series, as introduced by the frequency difference of the two oscillators, prevents coincidence between these two corresponding members of the two series in the absen'ceofthe delay provided. Similarly, the 'de'layprovided at the tapped point on delay line 55 to which switch 58 is connected is chosen to delay the series of impulses at tube 4| the interval required to bring the third member of that series into time coincidence With the third member of the series applied to grid 35 of tube 36. Likewise the delays at switches 59, 60, and BI are such as to bring coincidence between the corre- "sponding fourth, fifth and sixth members of the two series.

Let it be assumed that a group of signals is to be formed and that switches 56, 58, 59, and BI are selected and closed. An input impulse at terminals 2, as illustrated by waveform 15 of Fig. a to which joint reference is now had, produces the-gating voltage at multivibrator I represented by waveform It. Waveform l! is representative of the series of impulses applied to grid 35 of tube 35 in response to the input signal. Waveform it shows the series of impulses applied to delay line 55 by tube ll in response to the input signal. Since switch55 is closed at the input'tapped point on delay line 55 and no delay is introduced, there is time coincidence between initial'positive member llAof waveform Ti and initial member 18A of Waveform 18. This time coincidence unbiases tube 35 at both grids 35 and 62 simultaneously and output signal A of waveform85 appears at terminals '10. Waveforms 79, 80, "BI, '82, and 83 represent the voltage variations appearing at the tapped points to which switches 51 through 61, respectively, are connected. Since switches 5"! and 55 were not among those closed, there is no combination of series I! and series 19 or of series Ti and series 82. Switches 58, 59, and 6| we're-closed, however, to combine series TI with each of series 80, 81, and 83 to produce output signals 85C, 85D, and 85F at terminals 1B in response to the time coincidence of members 11C and 55C, 71D and Sill), and HF and 83F.

It is-obvious that the structure of the output pulse group at terminals 15 is selectable since any one of the six possible signals may be included or excludedby the selection'o'f 'the'proper switches 55 through 5|. reason for providing the multivibrator I with a period such that the series of impulses applied togrid 35'and any of the series at the delay line tap'points do not produce a second condition of coincidence. Examination of waveforms TI and T8 of Fig. l-reveals that a situation approaching, but not achieving, coincidence exists with respect toimpulses-HF and E36.

While the description of operation just given covers the use of the invention as a means of prcducinga group of signals of selectable group structure, its use asapparatus for increasing the useful range of artificial delay line 55 is quite similar. It will be seen that, if a delay line 55 is chosen to provide an accurate delay Tl between impulses 18F andt3F and only switch 5| 'isclosed, 'a totaldelay o'f'TZ, approximately eight'times Tl,

will occur between the application of an input Also obvious will be the signal at terminals 2 and the appearance of an output signal at terminals 10.

In a variant embodiment, such as that shown in Fig. 5, apparatus constructed and operated in accordance with the teachings of this invention may be employed to delay an electrical impulse without the use of a special delay element such as delay line 55 of Fig. 1. In Fig. 5, a multivibrator 90 shown in block form performs the same gating voltage producing function as multivibrator I of Fig. 1. Two means of producing series of signals comprising tubes 9|, 92, and. 93, and 94, 95, and 96, respectively, are provided, each similar in construction and operation to the means comprising tubes 8, 9, and I in Fig. l. Coincidence means 91 in block form performs the same function as tube 36 of Fig. 1.

In operation, oscillator 9| produces a sinusoidal voltage of a frequency slightly less than that of oscillator 94 so that the two series of impulses applied to coincidence means 91 are of slightly different periodicity. Further, resistors I00 and IOI are adjusted (in the manner hereinbefore described) to provide a predetermined time relation between the respective initial impulses. The severa1 waveforms of Fig. 6 illustrate the operation of this embodiment. Waveform I02 shows an input signal applied at terminals I03 of gating multivibrator 90. Waveform I04 shows the series of impulses produced by tubes SI, 92 and 93. Waveform I05 shows the corresponding series produced by tubes 94, 95 and 96. With the time relation shown between initial positive signal I04A and signal I05A of waveform I05, a delay of T3 is introduced between the application of input signal I02 and the production of output signal I06 at terminals I01. A range of delays is available, not only through adjustment of resistors I00 and IOI, but also through choice of the periodicity of the series of impulses.

Fig. '7 shows another variant embodiment also for delaying an electrical impulse. In this Fig. '7, a gate generator I II similar to the gate generator or multivibrator I employed in Fig. 1 is shown in block form. To the input terminals H2 of this generator is supplied a pulse type wave form as shown in I35 of Fig. 8, delayed re-- sponse to which is desired.

Dual tube circuit H3 comprising tubes H4 and' H5 and-dual tube circuit H6 comprising tubes H1 and H8 each represent conventional free running type multivibrators gated by means of the signal from generator III. Circuit H3 is responsive to a gated voltage at grid H9 of tube H4 to produce a series of rectangular positive impulses at plate I of tube H5 as shown in waveform I36 of Fig. 8. Similarly, circuit H6 is responsive to a gating voltage at grid I2I of tube H8 to produce a series of rectangular impulses at plate I22 of tube I I8 as shown in waveform I31 of Fig. 8. The periodicity and duration of these series of impulses may be fixed by suitable choice of the elements (typified by capacitors I23 and I24 and resistances I25 and I26, coupling tubes H4 and H5) connecting the dual tubes of circuits H3 and H6.

The rectangular impulse type waveforms produced at the plates I20 and I22 are applied through suitable resistance capacitance coupling networks to a biased coincidence tube I21 which is preferably of the multi-grid type. Tube I21 is maintained in a normally non-conductive condition'by a positive potential I28 applied to its cathode, grids I29 and I30 being normally at the ground or reference potential. Coincidence in time of an input impulse of each series after a.

total delay time T4 results in the production of the output signal at terminal I3I as shown in waveform I39 of Fig. 8. The rectangular impulse type waveform applied to grid I30 is preferably differentiated slightly by the coupling circuit including capacitance I32 and resistance I33 so that a delay circuit similar to the line 55 of Fig. 1 is not required. The differentiated waveform shown in I38 of Fig. 8 represents the actual voltage applied to grid I30 of tube I21. It is noted that the large amplijude initial negative excursion of the plate I22 of waveform I38 prevents conduction of the coincidence tube I21 inthe initial circuit operation so that the delay circuit is not required. The delay time may be adjusted quite closely by variation of the resistance I34 in the grid circuit of tube H1 which varies the duration of the interval between the impulses produced at the plate I22 of tube H8 and shown in waveform I 31 of Fig. 8. For a high degree of accuracy,

it may be desirable to stabilize the operation of the multivibrator H3 for accuracy.

Since certain further changes may be made in the foregoing constructions and different embodiments of the invention may be made without departing from the scope thereof, it is intended that all matter shown in the accompanying drawings or set forth in the accompanying specification shall be interpreted as illustrative and not in a limiting sense.

The invention described herein may be manufactured and used by or for the Government of the United States of America for govemmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. The method of generating a delayed signal comprising, receiving an input signal, producing in response to said input signal two non-harmonically related recurrent signals of different frequency which initially have a first predetermined phase relation, combining said two recurrent signals, and producing responsively to said two recurrent signals an output signal only when they assume a second predetermined phase relation.

2. The method of generating a delayed signal comprising, receiving an input signal, producing in response to said input signal two series of nonharmonically related recurrent signals of different periodicity the initial signals of which occur 55 with a first predetermined time relation, combining said two series of signals, and producing responsively to said two series of signals an output signal only when the subsequent signals of said two series occur with a second predetermined no time relation.

3. The method of generating a delayed signal comprising, receiving an input signal, producing in response to said input signal two series of nonharmonically related recurrent signals of differ- 86 ent periodicity the initial signals of which occur with a predetermined time relation, combining said two series of signals, and producing an output signal from said combination only when impulses of said series occur in time coincidence.

70 4. The method of producing a group of signals of selectable group structure comprising, receiving an input signal, producing in response to said input signal a first recurrent signal of one frequency, also producing in response to said input signal a plurality of recurrent signals each of a second. frequency non-harmonically related to the frequency of the first. signal and each having. a respective starting phase relation with said first recurrent signal, combining said first recurrent signal with said plurality of recurrent signals, and producing an output signal from said combination only when any one of said plurality of recurrent signals combined with said first recurrent signal assumes a, predetermined phase relation with respect thereto.

5. The method of producing av group of'signals of selectable group structure comprising, receiving an input signal, producing inresponse to said input signal a first series of. recurrent signals of one periodicity, also producing in response to said input signal a plurality of series of recurrent signals each of a second periodicity and frequency non-harmonically related to the frequency of the first series of recurrent signals, the initial member of each of which occurs ina respective starting time relation with the initial member of said first series, combining said first series withv said plurality of series, and producing an output signal only when any subsequent member of any of said plurality of series combined with said first series occurs in a predetermined time relation with any subsequent member of said first series.

6. The method of producing a group of signals of selectable group structure comprising, receiving an input signal, producing in response to said input signal a first series of recurrent signals of one periodicity, also producing in response to said inputsignal a plurality of series of recurrentsignals each of a second periodicity and frequency non-harmonically related to the frequency of the first series of recurrent signals, the initial member of each of which occurs in a respective starting time relation with the initial member of said first series, combining said first series with said pluralty of series, and producing an output signal only when any subsequent member of any of said plurality of series combined with said first series occurs in time coincidence with any subsequent member of said first series.

7. The method of generating a delayed signal comprising, receiving an input signal, producing in response to. said input signal a first sinusoidal voltage of one frequency, also producing in response to said input pulse a second sinusoidal voltage of another non-harmonically related frequency which starts in a predetermined phase relation with said first sinusoidal. voltage, generating from said first voltage a first series of recurrent signals with a fixed phase relation to said first voltage, generating from said second voltage a second series of recurrent signals with a fixed phase relation to said second voltage, combining said first and second series of signals, and producing responsively to the combination of said two recurrent signals an output signal only when said two recurrent signals assume a predetermined phase relation one to the other.

8. Apparatus for generating a delayed signal comprising, signal generating means responsive to an input signal for producing a plurality of nonharmonically related recurrent signals at least two of which have slightly different frequencies and initially have a first predetermined phase relation, and means including a vacuum tube coincidence circuit combining said recurrent signals for producing an output signal only when at least two of said recurrent signals assume a second predetermined phase relation.

9. Apparatus for producing a group of signals of selecable group structure comprising, signal generating means operative; at onefrequency and responsive to an input signal to produce a first recurrent signal of one frequency, means.- including a second signal generating means operative at a frequency non-harmonically related tothe frequency of the first signal generating means also. responsive to said; input signal to produce a selectable plurality of recurrent signals each of a second frequency slightly diiferent from said one frequency and each having a-v respective starting phase relation with said first recur-rent signal, means combining said first recurrent signal with, said plurality of recurrent signals, and means responsive to saidcombination' of signals producing an output signal when each of said plurality of signals combined; as-saidassumes a. predetermined: phase relation with respectto said first series.

10. Apparatus forproducing-a group of signals of selectable group structure comprising, signal generating means operative at; onefrequency and responsive to anv input signal to producea first series of recurrent signals of one periodicity, means including a second signal generating means operative at a frequency non-harmonically related'to the frequency of the-firstsignalgenerating means also responsive to saidinput signal to, produce a selectable plurality or series; of recurrent signals each of a second periodicity slightly different from said one periodicity the initial member of each ofwhich occurs in a respective, starting time relation with the initial member of said first series, means combining said first series with said plurality of series, and means responsive to said combination of series producing an output signal when any subsequent member of any ofsaid plurality of series combined' with said first series occurs in a predetermined time relation with any subsequentmember of said first series.

11. Apparatus for generating a delayed signal comprising, signal generating means operative at one frequency and responsive toan input signal to produce a first sinusoidal voltage of one; frequency, means including a second signal gene-ratingmeans operative at a frequency non-harmonically related. to the frequency ofthe first signal generating means also responsive to said input signal to produce a second sinusoid-al voltag-e'of another frequency which starts in a predetermined phase relation with said first sinusoidal voltage, means generating from saidfirstvoltage a first series of recurrent signals with a fixed phase relation to said first voltage, means: generating fromsaid second voltage a second series of recurrent signals with a fixed; phase relation to. said second voltage, means combining said firstand second series of'signals, and means producing responsively to the combination of said two recurrent. si nals n put s nal w en said two recurrent signals assume a predetermined. phase. relation one to the other.

12. Apparatus for generating a delayed; signal comprising, a pair of signal generators tuned to non-harmonically related frequencies responsive to an input signal to produce two sinusoidal voltages of different frequency which start with a predetermined phase relation, means producing from each of said sinusoidal voltages a series of recurrent signals, means delaying one of said series a selectable interval of time, means combining the other of said series and said delayed series, and means producing responsively to the series as combined an output signal when said 11 combined series assume a predetermined phase relation one to the other.

13. Apparatus for generating a delayed signal comprising, a signal generator tuned to one frequency and responsive to an input signal to produce a first sinusoidal voltage of one frequency, a second signal generator tuned to a frequency non-harmonically related to the frequency of the first signal generator also responsive to said input signal to produce a second sinusoidal voltage of another frequency which starts in phase with" said first sinusoidal voltage, means generating from said first voltage a first series of recurrent signals with a fixed phase relation to said first voltage, means generating from said second voltage a second series of recurrent signals with a fixed phase relation to said second voltage, means for delaying said second series of signals a selectable interval of time, means for combining said first series and said second series delayed as said, and means producing responsively to said two series as combined an output signals when said delayed series assumes a predetermined phase relation with said first series.

14. Apparatus for producing a group of signals of selectable group structure comprising, a signal generator tuned to one frequency and operatively responsive to an input signal to produce a first sinusoidal voltage of one frequency, a second signal generator tuned to a frequency nonharmonically related to the frequency of the first signal generator also operatively responsive to said input signal to produce a second sinusoidal voltage of another frequency slightly different from said one frequency which starts in phase 2: i with said first sinusoidal voltage, means producing from said first voltage a first series of recurrent signals with a fixed phase relation to said first voltage, means generating from said second voltage a second series of recurrent signals with a fixed phase relation to said second voltage, means for delaying said second series of signals a plurality of different intervals of time to produce therefrom a plurality of delayed series of signals, means combining said first series and said plurality of delayed series, and means producing responsively to said combination of series an output signal when each of said plurality of series combined with said first series assumes a predetermined phase relation with respect to said first series.

15. Apparatus for producing a group of signals of selectable group structure comprising, oscillator means responsive to an input signal for producing a predetermined number of cycles of a first sinusoidal voltage of one frequency, oscillator means also responsive to said input signal for producing a predetermined number of cycles of a second sinusoidal voltage of another frequency which starts in phase with said first sinusoidal voltage, vacuum tube means connected to first said oscillator for producing from said first voltage a first series of recurrent signals with a fixed phase relation to said first vacuum tube means and to each of said switching means operative to produce an output signal when each of said plurality of series ap plied thereto by said switching means assumes a predetermined phase relation with respect to said first series.

16. Apparatus for producing a group of signals of selectable group structure comprising, vacuum tube gating means responsive to an input pulse for producing a gating voltage, a first transitron oscillator connected to said gating means and keyed by said gating voltage for its duration to produce a first sinusoidal voltage of one frequency, a second transitron oscillator also connected to said gating voltage to produce for its duration a second sinusoidal voltage of another frequency which startes in phase with said first sinusoidal voltage, vacuum tube generating means connected to said first oscillator for generating from said first voltage a first series of recurrent signals with a fixed phase relation to said first voltage, vacuum tube generating means connected to said second oscillator for generating from said second voltage a second series of recurrent signals with a fixed phase relation to said second voltage, a delay line tapped at a plurality of delay defining points connected to receive and delay the output of last said vacuum tube generating means, a plurality of switching means each connected to a respective tapped point on said delay line, and vacuum tube coincidence means connected to first said vacuum tube generating means and to each of said switching means for producing an output signal in response to each simultaneous application of signals thereto by said first vacuum tube means and said switching means.

CONRAD H. HOEPPNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,145,332 Bedford Jan. 31, 1939 2,425,600 Kendall Aug. 12, 1947 FOREIGN PATENTS Number Country Date 510,881 Great Britain Aug. 8, 1939 

